#1426. 【2022.5.21 联考】空

https://sjzezoj.com/submission/53072

S2OJ/1426/1426.cpp

@@ -0,0 +1,71 @@
+#include <algorithm>
+#include <iostream>
+#include <queue>
+#include <utility>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 2e5 + 5;
+
+int n, ans;
+std::pair<int, int> lines[N];
+
+// 包含
+std::priority_queue<
+    std::pair<int, int>,
+    std::vector<std::pair<int, int>>,
+    auto(*)(std::pair<int, int>, std::pair<int, int>)->bool>
+q1([](std::pair<int, int> a, std::pair<int, int> b) -> bool {
+    return a.second - a.first < b.second - b.first;
+});
+
+// 相交
+std::priority_queue<
+    std::pair<int, int>,
+    std::vector<std::pair<int, int>>,
+    auto(*)(std::pair<int, int>, std::pair<int, int>)->bool>
+q2([](std::pair<int, int> a, std::pair<int, int> b) -> bool {
+    return a.first + a.second > b.first + b.second;
+});
+
+int main() {
+    std::ios::sync_with_stdio(false);
+
+    cin >> n;
+
+    for (int i = 1; i <= n; i++) {
+        cin >> lines[i].first >> lines[i].second;
+    }
+
+    std::sort(lines + 1, lines + 1 + n);
+
+    q1.push(lines[1]);
+    q2.push(lines[1]);
+
+    for (int i = 2; i <= n; i++) {
+        while (!q1.empty() && lines[i].second >= q1.top().second) q1.pop();  // 剔除已经相交的线段
+        while (!q2.empty() && lines[i].first >= q2.top().second) q2.pop();   // 剔除已经相离的线段
+
+        if (!q1.empty()) {
+            auto p = q1.top(),
+                 q = lines[i];
+            ans = std::max(ans, (p.second - p.first) - (q.second - q.first));
+        }
+
+        if (!q2.empty()) {
+            auto p = q2.top(),
+                 q = lines[i];
+            ans = std::max(ans, (q.second - p.second) + (q.first - p.first));
+        }
+
+        q1.push(lines[i]);
+        q2.push(lines[i]);
+    }
+
+    cout << ans << endl;
+
+    return 0;
+}